> ## Documentation Index
> Fetch the complete documentation index at: https://developers.fd.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Commerce Protocols

> x402, ACP, UCP — the emerging protocols enabling AI agents to shop, and how Prism abstracts them.

Multiple companies are building protocols for AI agent commerce — each covering a different part of the journey from product discovery to payment. Prism is protocol-agnostic: you integrate once, and Prism handles protocol translation behind the scenes. When a new protocol gains traction, Prism adds support without changing your integration.

## The Protocol Landscape

| Layer                  | Protocol | Created By               | Status                               |
| ---------------------- | -------- | ------------------------ | ------------------------------------ |
| Settlement (payment)   | x402     | Coinbase (open standard) | **Live** — Prism uses this today     |
| Checkout (transaction) | ACP      | OpenAI                   | **Live** — Prism supports this today |
| Full Commerce Journey  | UCP      | Google                   | **Live** — Prism supports this today |

These protocols are complementary, not competing. x402 handles the settlement layer — the actual movement of money. ACP and UCP handle the commerce layer — product discovery, cart management, checkout flow. An agent might use ACP to find and select a product, then x402 (via Prism) to pay for it.

## x402 — Settlement Protocol

x402 implements the HTTP 402 "Payment Required" status code for machine-to-machine stablecoin payments. It's Prism's primary protocol today.

**How it works:** Agent requests a resource → server responds 402 with payment requirements → agent pays on-chain → server grants access.

**Best for:** API monetization, data feeds, premium content, pay-per-request services — any endpoint where access requires payment.

**Status:** Live. This is what you integrate with today.

[Full x402 documentation →](/prism/integrations/x402)

## ACP — Agent Commerce Protocol

Created by OpenAI for structured AI agent commerce. ACP covers the full commerce journey: product discovery, cart management, checkout, payment, and order lifecycle. It's designed for scenarios where an agent needs to browse a catalog, select products, and complete a purchase.

**How Prism integrates:** ACP handles the commerce flow (what the agent is buying). Prism handles the settlement (how the agent pays) via the `xyz.fd.prism_payment` handler. Merchants get:

* AI agents that can browse their product catalog programmatically
* Structured checkout with stablecoin settlement via Prism
* The same instant settlement and zero chargebacks as x402

**Best for:** E-commerce product purchases, multi-item orders, any scenario with a traditional checkout flow.

**Status:** Live. Prism supports ACP via the `xyz.fd.prism_payment` handler today.

[Full ACP integration guide →](/prism/integrations/acp)

## UCP — Universal Commerce Protocol

Created by Google for the full commerce journey — from discovery to post-purchase. UCP is more comprehensive than ACP, covering the entire lifecycle: discovery, selection, purchase, fulfillment, returns, and support.

**How Prism integrates:** Prism serves as the settlement and payment verification layer within the UCP flow.

**Best for:** Complex multi-step purchases, scenarios requiring fulfillment tracking, subscription-like flows.

**Status:** Live. Prism supports UCP via the `xyz.fd.prism_payment` handler today.

[Full UCP integration guide →](/prism/integrations/ucp)

## How Prism Abstracts Protocol Complexity

```mermaid theme={"theme":{"light":"github-light","dark":"one-dark-pro"}}
flowchart LR
    X402[x402] --> P["Prism\n(Gateway)"]
    ACP[ACP] --> P
    UCP[UCP] --> P
    P --> App["Your Application\n(single SDK / API)"]
```

The key insight: **you integrate Prism once**. Prism handles protocol translation on the inbound side. Whether an agent pays via x402, initiates checkout via ACP, or goes through a full UCP commerce journey — your SDK integration and webhook handling stay the same.

This protects your investment. As the protocol landscape evolves, you don't need to re-integrate. Prism adapts; your code doesn't change.

## What Should I Use Today?

<CardGroup cols={2}>
  <Card title="x402 — Start Here" icon="bolt" href="/prism/integrations/x402">
    x402 is live and supported today. Ideal for API monetization and
    pay-per-request models.
  </Card>

  <Card title="Quick Start" icon="rocket" href="/prism/quickstart">
    Integrate x402 payment protection in minutes with the Prism SDK.
  </Card>
</CardGroup>

If you're building an e-commerce platform, integrate Prism now with x402, UCP, or ACP (all live today). They use the same `xyz.fd.prism_payment` handler and settle via the same Prism API.